A popular rotary piston engine is the oscillatory rotating arrangement which employs a plurality of rotors with interleaved pistons, or vanes, around the center of rotation. By changing the angular velocity of the rotors, an oscillatory movement is superimposed on their uniform rotation, thus modifying the volume of the energy chambers defined by each pair of adjacent pistons and the inner surface of the engine housing.
The number of pistons on each rotor is equal to the number of contraction and expansion regions of the housing in an oscillatory rotating engine. As each chamber goes through an expulsion stroke it travels or rotates through the spacing between the expulsion port and the intake port. In the spacing the chamber experiences conditions which produce a sort of short non-actuation period where it can neither expand nor contract. The two rotors defining the actuation of the chamber translates these non-actuation characteristics to all chambers exclusively defined by the two rotors. In all cases, the number of chambers that experience non-continuous actuation as each chamber passes the port spacing is equal to the number of individual vanes on each rotor.
There are many examples of oscillatory rotating engines, such as disclosed in, for example, U.S. Pat. Nos. 1,973,397; 6,293,775; and 3,744,938, the disclosures of which are all incorporated herein by reference as well as my earlier U.S. patent application Ser. No. 10/818,864, filed Apr. 6, 2004, the disclosure of which is hereby incorporated by reference in its entirety. The design particulars of previous oscillatory rotating engines involve scissor action where all alternate chambers actuate diametrically opposed strokes. The non-actuation period of the two rotors makes all chambers stop actuating for a time between every single stroke, producing coupling harmonics that require robust and sophisticated gears and flywheels. Furthermore, continuous combustion is difficult to achieve in previous designs without transfer ports.
Another type of rotary engine of interest is the quasi-turbine (Qurbine) described in, for example, U.S. Pat. Nos. 6,164,263 and 6,899,075, the disclosures of which are incorporated herein by reference. The Qurbine includes an assembly of four carriages supporting the pivots of four pivoting blades forming a variable-shape rotor. This rotor rolls like a roller bearing on the interior surface of an obround housing. During rotation, the rotor pivoting blades align alternatively in a lozenge and a square configuration. A central shaft is added and driven by the blades through an arrangement of mechanical arms.
High frequency opening and closing ports of high pressure vapor often produce large shock wave harmonics, making vibration tolerance a major limiting factor for power density and gear train design. Previous rotary engines often use sophisticated gear and crank actuation mechanisms where turning the shaft induces an oscillatory rotary movement. These mechanisms often more than double the size and weight of the total engine.
Accordingly, it will be appreciated by those of ordinary skill in the art that there is a need for an improved oscillatory rotating engine that simplifies the transfer of torque to the output shaft while coming closer to a continuous combustion engine.